The invention relates to the field of fluid or gas volume measurement and, more particularly, to a highly accurate measurement of fluid level under adverse conditions.
The measure of the fluid level in a container, particularly in a irregularly shaped container, can be accomplished by measuring the volume of gases above the liquid and subtracting from the known total volume of the container. Therefore, the same method may be used for measuring the volume of a gas or a liquid.
The measurement of fluid levels as in the gasoline tank of a vehicle has relied, almost exclusively, on some type of float device coupled to a potentiometer. While such an arrangement can provide a rough estimate of the fuel remaining in the tank, it is inaccurate under the best of conditions and is subject to many error-causing factors. The inherent inaccuracy is due to such things as the increasingly shallower tanks of present day vehicles, the irregular shapes of most tanks and the mechanical problems of the float/potentiometer combination. Variable factors include the effects of driving terrain and vehicle loading. With the use of a voltage or current meter as the readout device, there was no need or demand for precise measurement, but with the present day use of microprocessors and digital readouts, as well as the emphasis on fuel conservation, a more accurate measurement and readout are both possible and desirable. The same measuring arrangement can, of course, be applied to the measurement of the volume of a container, the volume of gas above a liquid in a container or the amount of liquid in a container. It would be desirable to have an arrangement which can very simply be adapted to different sizes of container. It would also be desirable to additionally provide an indication when the container is left uncapped. Additionally, it would be desirable to utilize a basic liquid volume measurement to provide a corollary reading such as miles per gallon in a vehicle.